Use Codex with Your ChatGPT Account

Before you start

Use a ChatGPT account with access to Codex. The models you can select and your usage limits depend on that account.

For a managed workspace, an administrator may need to allow device-code sign-in first.

First, enable device code sign-in in ChatGPT:

1. Open your account menu and choose Settings.

2. Select Security and login in the settings sidebar.
3. Scroll to the bottom and turn on Enable device code sign-in for Codex, Excel, PowerPoint, and Word.

Then return to Agent Zero. OpenAI also documents this setting in its device-code sign-in instructions.

1. Open the Account setup

Open Agent Zero and send a message from the welcome screen. For example: Help me understand what Agent Zero can do for me.

Agent Zero creates a chat and holds your message while you connect a model. Click AI account in the chat. If onboarding is already open, select its Account tab.

On the Codex/ChatGPT card, click Connect account to pick Codex.

This opens Choose your main model. Click Connect account on this screen to start sign-in.

2. Copy your device code

Agent Zero opens an OpenAI sign-in page in another browser tab. Return to the Agent Zero tab to copy the Device code shown under Waiting for sign-in. You can select the code, right-click it, and choose Copy.

Keep the Agent Zero tab open while you finish signing in. Keep the code private and use only the code from the connection you just started.

3. Authorize on OpenAI's page

Switch to the OpenAI tab and check that the address is on auth.openai.com. Choose the ChatGPT account you want Agent Zero to use. If it is not listed, click Use another account and sign in.

Paste the code from Agent Zero into the device-code fields, then click Continue. OpenAI's page calls this access to Codex CLI; this is the sign-in flow Agent Zero uses for the connection you started.

Wait for Signed in to Codex. You can then close that tab and return to Agent Zero.

4. Choose the Main model

Back in Agent Zero, wait for the account to show a green checkmark. The model list becomes available once the connection completes.

Click Main model or its search icon. Choose gpt-6.1-terra if it is available in your account. You can type part of its name to narrow the list. This is the model that handles your conversation and work.

Click Choose utility model to continue.

5. Choose the Utility model

Keep Utility provider set to Codex/ChatGPT Account and select gpt-6-luna if it is available. The Utility model handles shorter tasks such as summaries and chat names.

These are Agent Zero's onboarding suggestions when available. You can choose different models from your account's list; the available names may change over time. Check both choices, then click Finish setup. This saves your choices and resumes the held message in its original chat.

6. Continue in your original chat

The Agent Zero is ready screen confirms setup. The extra connection cards are optional. Click Continue to close onboarding.

The reply to your first message appears in the same chat. There is no need to send the message again or create another chat. You can carry on with a follow-up question.

To change models later, open the preset menu above the composer and choose Edit Presets. See Model Presets for the details.

If something gets stuck

• The OpenAI tab did not open: allow pop-ups for your Agent Zero address. Cancel the pending sign-in, then click Connect account again.
• Device-code login is unavailable: check the ChatGPT security setting or ask your workspace administrator to allow it.
• The code expired or was rejected: cancel the pending sign-in in Agent Zero and start a new connection. Copy the newly displayed code.
• OpenAI says you are signed in, but Agent Zero is still waiting: return to the Agent Zero tab and give it a moment to update. If it reports an error, start sign-in again.
• The model list is empty: finish signing in first. If the account is connected, open the model field again to retry loading the list. Choose a model your account can access.

For API keys, local models, and the other account providers, see First-Run Onboarding.